Thermoplastic resin composition

ABSTRACT

A thermoplastic resin composition affording a delustered shaped article which comprises (A) a rubber-modified copolymer with (B) an epoxy group-containing olefin polymer or an unsaturated carboxylic acid-modified olefin polymer (B&#39;).

This application is a continuation, of application Ser. No. 746,689,filed June 20, 1985, now abandoned, which in turn is a divisional ofSerial. No. 549,381, filed November 7, 1983, now U.S. Pat. No.4,554,316.

The present invention relates to a thermoplastic resin composition. Moreparticularly, it relates to a theroplastic resin composition comprisinga rubber-modified copolymer which can provide a delustered (low gloss)shaped article.

Rubber-modified copolymers such as graft polymers of aromatic vinylcompounds, vinyl cyanides and/or alkyl unsaturated caroboylates ontorubbery polymers (e.g. acrylonitrile-butadiene rubber-styrene copolymer(ABS resin), methyl methacrylate-butadiene rubber-styrene copolymer (MBSresin), acrylonitrile-butadiene rubber-styrene-methyl methacrylatecopolymer (ABSM resin), acrylonitrile-ethylene/propylene rubber-styrenecopolymer (AES resin) are widely used in various fields due to theirexcellent and well-balanced physical properties. Particularly, they areused for manufacture of interior and exterior articles in automobiles.

In recent years, the interior articles of automobiles are frequentlydesired to be delustered (reduced the gloss) from the viewpoint ofsafety and harmony with other parts. For manufacture of delusteredarticles, there are usually adopted two procedures, of which one is theprocedure using a mold having a special surface and the other is theprocedure using a special material. In the former procedure, a resincompositin to be molded is so closely contacted with a mold having anembossed surface that the abrasion of the mold is remarkable. Therefore,embossing is required to be carried out repeatedly. Further, the stateof luster (gloss) is varied with the conditions for molding. In thelatter procedure, a filler or a rubbery polymer is incorporated into aresin composition to be molded, but the filler incorporation is notdesirable in deterioration of the physical properties as well as theappearance, while the rubbery polymer incorporation is not favorable inproducing a flow marks or wel marks to deteriorate the quality.

As a result of the extensive study, it has now been found that theincorporation of a certain polymeric material into a rubber-modifiedcopolymer makes a shaped article of such rubber-modified copolymerdelustered (low gloss) without any substantial deterioration of theexcellent physical properties inherent thereto. This invention is basedon the above finding.

According to the present invention, there is provided a thermoplasticresin composition comprising (A) a rubber-modified copolymer with (B) anepoxy group-containing olefin polymer or (B') an unsaturated carboxylicacid-modified olefin polymer, which can provide a shaped article beingdelustered.

The rubber-modified copolymer which is the component (A) is obtainableby polymerizing at least two kinds of monomers chosen from aromaticvinyl compounds, vinyl cyanides and alkyl unsaturated carbonxylates inthe presence of a rubber(s). The resulting product comprises (a-1) acopolymer comprising units of the rubber and units of the monomers graftpolymerized thereon (hereinafter referred to as "graft copolymer")usually with (a-2) a copolymer comprising units of the monomers(hereinafter referred to as "copolymer"). Alternatively, the graftcopolymer (a-1) and the copolymer (a-2) may be separately produced andcombined together to make a uniform composition usable as the component(A). In general, the rubber-modified copolymer (A) comprises the graftcopolymer (a-1) and the copolymer (a-2) respectively in amounts of 5 to100% by weight and of 95 to 0% by weight on the basis of the weight ofthe rubber-modified copolymer (A). When the content of the graftcopolymer (a-1) is less than 5% by weight, the ultimate composition willbe insufficient in impact strength.

The weight proportion of the rubber and the monomers in the graftcopolymer (a-1) is normally from 5 : 95 to 70 : 30. The composition ofthe monomers is not limitative and may comprise, for instance, anaromatic vinyl compund(s) in a content of 50 to 80% by weight and avinyl cyanide(s) and/or an alkyl unsaturated carboxylate(s) in a contentof 50 to 20% by weight. No particular restriction is present on theparticle size of the graft copolymer (a-1), and it may be usually from0.05 to 5 micron, favorabley from 0.1 to 0.5 micron.

The composition of the monomers in the copolymer (a-2) is also notlimitative and may comprise, for instance, an aromatic vinyl compound(s)in a content of 50 to 90% by weight and a vinyl cynadine(s) and/or analkyl unsaturated carboxylate(s) in a content of 50 to 10% by weight. Nospecial limitation is present on the intrinsic viscosity of thecopolymer (a-2), and it may be ordinarily from 6.0 to 1.50 (whendetermined in dimethylformamide at 30° C.).

Examples of the rubber for the graft copolymer (a-1) are polybutadiene,styrene/butadiene copolymer, acrylonitrile/butadiene copolymer,ethylene/propylene copolymer, ethylene/propylene/non-conjugated diene(e.g. dicyclopentadiene, ethylidenenorbornene, 1,4-cyclohexadiene,1,4-cycloheptadiene, 1,5-cyclooctadiene) copolymer, ethylene/vinylacetate copolymer, chlorinated polyethylene, polyalkyl acrylate, etc. Incase of the ethylene/propylene copolymer or theethylene/propylene/non-conjugated diene copolymer, the molar ratio ofethylene and propylene may be from 5 : 1 to 1 : 3. The non-conjugateddiene content in the ethylene/proplene/non-conjugated diene copolymer ispreferred to be from 2 to 50 in terms of iodine value. Examples of thearomatic vinyl compound(s) are styrene, α-methylstyrene,methyl-α-methylstyrene, vinyltoluene, monochlorostyrene, etc. Examplesof the vinyl cyanide(s) are acrylonitrile, methacrylonitrile, etc.Examples of the alkyl unsaturated carboxylate(s) are alkyl acrylates(e.g. methyl acrylate, ethyl acrylate, butyl acrylate), alkylmethacrylates (e.g. methyl methacrylate, ethyl methacrylate, butylmethacrylate), hydroxyalkyl acrylates (e.g. hydroxyethyl acrylate,hydroxypropyl acrylate), hydroxyalkyl methacrylate (e.g. hydroxyethylmethacrylate, hydroxypropyl methacrylate), etc.

For preparation of the rubber-modified copolymer (A), there may beadopted any conventional polymerization procedure such as emulsionpolymerization, suspension polymerization, bulk polymerization, solutionpolymerization, emulsion-suspension polymerization and bulk-suspensionpolymerization.

The epoxy group-containing olefin polymer (B) is a copolymer of at leastone of unsaturated epoxy compounds and at least one of olefins with orwithout at least one of ethylenically unsaturated compounds. While nospecial limitation is present on the composition of these monomers, thecontent of the unsaturated epoxy compound(s) is preferred to be from 0.5to 95% by weight.

As the unsaturated epoxy compound(s), there may be used the ones havingan unsaturated group copolymerizable with an olefin and an ethylenicallyunsaturated compound as well as an epoxy group in the molecule. Forinstance, unsaturated glycidyl esters, unsaturated glycidyl ethers,epoxyalkenes, p-glycidylstyrenes, etc. are usable. Those of thefollowing formulas are also usable: ##STR1## wherein R is a C₂ -C₁₈hydrocarbon group having an ethylenic unsaturation, R' is a hydrogenatom or a methyl group and X is --CH₂ O--, ##STR2## or ##STR3## Morespecifically, the following compounds are exemplified: glycidylacrylate, glycidyl methacrylate, glycidyl itaconate, butenecarboxylates,allyl glycidyl ether, 2-methylallyl glycidyl ether, styrene-p-glycidylether, 3,4-epoxybutene, 3,4-epoxy-3-methyl-1-butene,3,4-epoxy-1-pentene, 3,4-epoxy-3-methyl-pentene, 5,6-epoxy-1-hexene,vinylcyclohexene monoxide, p-glycidylstyrene, etc.

Examples of the olefin(s) are ethylene, propylene, butene-1,4-methylpentene-1, etc.

As the ethylenically unsaturated compound(s), there are exemplifiedolefins, vinyl esters having a C₂ -C₆ saturated carboxylic acid moiety,acrylic and methacrylic esters having a C₁ -C₈ saturated alcohol moiety,maleic esters having a C₁ -C₈ saturated alcohol moiety, vinyl halides,vinyl ethers, N-vinyllactams, carbonamides, etc. These ethylenicallyunsaturated compounds may be copolymerized with the unsaturated epoxycompounds and the olefins in an amount of not more than 50% by weight,especially from 0.1 to 45% by weight based on the total weight of themonomers to be copolymerized.

The epoxy group-containing olefin polymer (B) may be prepared by variousprocedures, of which one typical example comprises contacting theunsaturated epoxy compound(s) and the olefin(s) with or without theethylenically unsaturated compound(s) onto a radical generating agent ata temperature of 40 ° to 300° C. under a pressure of 50 to 4000 atm.Another typical example comprises irradiating gamma-rays to a mixture ofpolypropylene with the unsaturated epoxy compound(s) under a high degreeof reduced pressure.

The unsaturated carboxylic acid-modified olefin polymer (B') is acopolymer of at least one of unsaturated carboxylic acids and theiranhydrides and at least one of olefins with or without at least one ofethylenically unsaturated compounds. While any particular limitation isnot present on the composition of these monomers, a preferred weightproportion of the unsaturated carboxylic acids and their anhydrides, theolefins and the ethylenically unsaturated compounds is0.01-20:99.9-5:0-50. In other words, the content of the unsaturatedcarboxylic acid(s) and /or their anhydride(s) is preferred to be from0.01 to 20% by weight on the basis of the total weight of the monomers.

Examples of the unsaturated carboxylic acids and their anhydrides aremonocarboxylic acids such as acrylic acid and methacrylic acid,dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid,dicarboxylic acid anhydrides such as maleic anhydride and itaconicanhydride, etc. Especially preferred are dicarboxylic acids and theiranhyrides.

As the olefins, there may be exemplified ethylene, propylene, butene-1,methylpentene-1, etc. Ethylene and propylene are particularly favored.

As the ethylenically unsaturated compounds, there are exemplifiedolefins, vinyl esters of C₂ -C₆ saturated carboxylic acids, C₁ -C₈ alkylesters of acrylic or methacrylic acid, C₁ -C₈ alkyl esters of maleicacid, vinyl halides, vinyl ethers, N-vinyllactams, carbonamides, etc.

The unsaturated carboxylic acid-modified olefin polymer (B') may beprepared by various procedures, of which one typical example comprisesadding the unsaturated carboxylic acid and/or its anhydride to a polymerof the olefin with or without the ethylenically unsaturated compound andheating the resultant mixture.

No particular restriction is present on the amount of the epoxygroup-containing olefin polymer (B) or the unsaturated carboxylicacid-modified olefin polymer (B') to be incorporated, and it may beusually from 0.1 to 40 parts by weight to 100 parts by weight of theweight of the rubber-modified copolymer (A). When the amount is lessthan the lower limit, a satisfactory dispersibility is not assured. Whenmore than the upper limit, layer separation is apt to be formed in theshaped product. In view of the impact strength, weld strength andprocessability of the thermoplastic resin composition, the amount of theepoxy group-containing olefin polymer (B) or the unsaturated carboxylicacid-modified olefin polymer (B') is particularly preferred to be from0.5 to 10 parts by weight.

For preparation of the thermoplastic resin composition of the invention,the said essential components may be mixed together in any optionalorder. Ford instance, all of them may be mixed together. Further, forinstance, two of them may be first mixed together, followed byintroduction of the remaining one into the resultant mixture. Mixing maybe achieved by the use of any conventional mixing apparatus such asBambury mixer, a monoaxial extruder or a biaxial extruder. If desired,any other resin such as a polyolefin resin (e.g. polyethylene,polypropylene, ethylene/propylene copolymer) and/or any additive(s) sucha dyestuffs, pigments, stabilizer, plasticizers, antistatic agents,ultraviolet ray absorbers, flame retardant agents, lubricants andfillers may be incorporated into the thermoplastic resin composition.

Practical and presently preferred embodiment of the invention areillustratively shown in the following Examples wherein % and part(s) areby weight unless otherwise indicated.

EXAMPLES 1 to 3 AND COMPARATIVE EXAMPLES 1 to 4

According to the prescription as shown in Table 1, the rubber-modifiedcopolymer (A) and the epoxy group-containing olefin polymer (B) or aconventional delustering agent (gloss reducing agent) were mixedtogether by the aid of a Bambury mixer. The resultant mixture waspelletized, and the pellets were molded to make a test piece. The testpiece was subjected to measurement of the physical properties includingthe surface gloss. The results are shown in Table 1.

The rubber-modified copolymer (A) as used was a heat resistant ABS resin"KRALASTIC K-2938A" manufactured by Sumitomo Naugatuck Co., Ltd.

The epoxy group-containing olefin polymer (B) was the one manufacturedas set forth below:

In an autoclave, a mixture of ethylene and glycidyl methacrylate with orwithout vinyl acetate pressurized to 2000 kg/cm² was charged, anddi-t-butyl peroxide as the catalyst was introduced therein. Theresultant mixture was maintained at a temperaature of 150° to 300° C.while stirring for several minutes, during which bulk polymerizationproceeded. From the reaction mixture, the produced copolymer wasseparated and recovered by the aid of a separator.

                                      TABLE 1                                     __________________________________________________________________________                     Example     Comparative Example                              Composition      1   2   3   1   2   3   4                                    __________________________________________________________________________    Rubber-modified copolymer (A)                                                                  100 100 100 100 100 100 100                                  (part(s)) ABS resin                                                           Epoxy group-containing olefin                                                 polymer (B) (part(s))                                                         (i) E-GMA-VA*.sup.1                                                                            3   --  1   --  --  --  --                                   (ii) E-GMA*.sup.2                                                                              --  5   --  --  --  --  --                                   Talc*.sup.3 (part(s))                                                                          --  --  --  --   5  --  --                                   Styrene-butadiene block polymer*.sup.4                                                         --  --  --  --  --  3   5                                    Notched Izod impact strength                                                                   18.5                                                                              17.5                                                                              18.8                                                                              18.0                                                                              10.0                                                                              19.0                                                                              19.5                                 (1/4", 23° C.) (kg · cm/cm.sup.2)                             Heat distortion temperature                                                                    98.0                                                                              97.5                                                                              98.3                                                                              98.5                                                                              105 92.0                                                                              90.5                                 (264 psi, no annealing) (°C.)                                          Flow mark        No  No  No  No  Yes Yes Yes                                  Gloss (deluster) 25  20  30  90  40  55  45                                   (60° specular gloss) (%)                                               __________________________________________________________________________     Notes:                                                                        *.sup.1 Ethyleneglycidyl methacrylatevinyl acetate copolymer (molar ratio     = 90:7:3)                                                                     *.sup.2 Ethyleneglycidyl methacrylate copolymer (molar ratio = 90:10)         *.sup.3 "Micron white No. 5000" manufactured by Hayashi Kasei                 *.sup.4 "Toughprene" manufactured by Asahi Kasei                         

EXMAPLES 4 to 6 AND COMPARATIVE EXAMPLES 5 to 8

According to the prescription as shown in Table 2, the rubber-modifiedcopolymer (A) and the epoxy group-containing olefin polymer (B) or aconventional delustering agent (gloss reducing agent) were mixedtogether by the aid of Bambury mixer. The resultant mixture waspelletized, and the pellets were molded to make a test piece. The testpiece was subjected to measurement of the physical properties includingthe surface gloss. The results are shown in Table 2.

The rubber-modified copolymer (A) as used was the one manufactured asset forth below:

Ethylene-propylene-ethylidene norbornene copolymer (iodine value, 8.5;Mooney viscosity, 61; propylene content, 43%) (20 parts), styrene (55parts) and acrylonitrile (25 parts) were subjected to polymerization bya conventional solution polymerization procedure to obtain as AES resin(I).

Ethylene-propylene-ethylidene norbornene copolymer (iodine value, 8.5;Mooney viscosity, 61; propylene content, 43%) (30 parts), styrene (50parts) and acrylonitrile (20 parts) were subjected to polymerization bya conventional suspension polymerization procedure to produce a resin.The resin was admixed with styrene-acrylonitrile copolymer (weightratio=70 : 30) prepared by suspension polymerization in a weightproportion of 1 : 1 in the state of beads to obtain an AES resin (II).

The epoxy group-containing olefin polymer (B) was the one as used inExamples 1 to 3.

                                      TABLE 2                                     __________________________________________________________________________                      Example     Comparative Example                             Composition       4   5   6   5   6   7   8                                   __________________________________________________________________________    Rubber modified copolymer (A)                                                 (part(s))                                                                     AES resin (I)     100 100 --  100 100 100 --                                  AES resin (II)    --  --  100 --  --  --  100                                 Epoxy group-containing olefin                                                 copolymer (B) (part(s))                                                       (i) E-GMA-VA*.sup.1                                                                             3   --  1   --  --  --  --                                  (ii) E-GMA*.sup.2 --  5   --  --  --  --  --                                  Talc*.sup.3 (parts(s))                                                                          --  --  --  --   5  --  --                                  Styrene-butadiene block polymer*.sup.4                                                          --  --  --  --  --  3   5                                   Notched Izod impact strength                                                                    48.5                                                                              51.5                                                                              35.0                                                                              43.3                                                                              12.5                                                                              48.3                                                                              51.5                                (1/4", 23° C.) (kg · cm/cm.sup.2)                             Heat distortion temperature                                                                     90.5                                                                              90.5                                                                              91.0                                                                              90.0                                                                              94.0                                                                              85.0                                                                              84.3                                (264 psi, no annealing) (°C.)                                          Flow mark         No  No  No  No  Yes Yes Yes                                 Gloss (deluster)   15 10  35  95  20-55                                                                             75  65                                  (60° specular gloss) (%)                                               Weather resistance (after exposure                                            by Weather-O-Meter for 1000 hours)                                            Izod impact strength without                                                                    175 190 145 155 75  83  72                                  notch (1/8", -30° C.) (kg · cm/cm.sup.2)                      Color difference (ΔE)                                                                     1.5 2.0 2.0 1.8 2.1 8.5 10.8                                __________________________________________________________________________     Notes: *.sup.1 *.sup.2 *.sup.3 and *.sup.4 same as in Table 1.           

EXAMPLES 7 AND 8

According to the prescription as shown in Table 3, the rubber-modifiedcopolymer (A) and the unsaturated carboxylic acid-modified olefinpolymer (B') were mixed together by the aid of Bambury mixer. Theresultant mixture was pelletized, adn the pellets were molded to make atest piece. The test piece was subjected to measurement of the physicalproperties including the surface gloss. The results are shown in Table3.

The rubber-modified copolymer (A) as used was the heat resistant ABSresin "KRALASTIC K-2938A" as used in Example 1 or the AES resin (I) asused in Example 4.

The unsaturated carboxylic acid-modified olefin polymer (B') was the onemanufactured as set forth below:

Maleic anhydride (0.5 part) was added to powdery polyethylene (100parts), and the resultant mixture was kneaded well by two rolls at 200°C. for about 3 minutes and shaped to obtain a sheet. After cooling, thesheet was pulverized by the aid of a die of 3 mm square.

                  TABLE 3                                                         ______________________________________                                                             Example                                                  Composition            7       8                                              ______________________________________                                        Rubber-modified copolymer (A)                                                 (part(s))                                                                     ABS resin              100     --                                             AES resin (I)          --      100                                            Unsaturated carboxylic acid                                                                          3       3                                              modified olefin polymer                                                       (B') (part(s))                                                                Notched Izod impact strength                                                                         18.0    45.0                                           (1/4", 23° C.) (kg · cm/cm.sup.2)                             Heat distortion temperature                                                                          98.0    90.5                                           (264 psi, no annealing) (°C.)                                          Flow mark              No      No                                             Gloss (deluster)       28      20                                             (60° specular gloss) (%)                                               Weather resistance (after exposure                                            by Weather-O-Meter for 1000 hours)                                            Izod impact strength without                                                                         --      165                                            notch (1/8", -30° C.) (kg · cm/cm.sup.2)                      Color difference (ΔE)                                                                          --      1.8                                            ______________________________________                                    

What is claimed is:
 1. A delustered shaped article prepared by molding athermoplastic resin composition which comprises(A) a rubber-modifiedcopolymer obtained by polymerizing at least two kinds of monomersselected from different members of the group consisting of aromaticvinyl compounds, vinyl cyanides and alkyl unsaturated carbonylates inthe presence of at least one of rubbers, said rubber-modified copolymer(A) comprising (a-1) a graft copolymer comprising (i) a rubbercomprising units from a diene and (ii) units of at least two kinds ofmonomers selected from the group consisting of styrene, acrylonitrileand methyl methacrylate graft polymerized thereon and (a-2) a copolymercomprising units of at least kinds of monomers chosen from styrene oralpha-methylstyrene, acrylonitrile and methyl methacrylate, the contentsof the graft copolymer (a-1) and the copolymer (a-2) being respectivelyfrom 5 50% by weight and 50 to 95% by weight based on the weight of therubber-modified copolymer (A), and (B') an unsaturated carboxylicacid-modified olefin polymer which is a copolymer of reactantscomprising unsaturated carboxylic acid or anhydride thereof and olefin,the weight proportion of the rubber-modified olefin copolymer (A) andthe unsaturated carboxylic acid-modified olefin polymer (B') in saidcomposition being 100:0.5-40.